NetBIOS stands for "Network Basic Input Output System". It was originally developed by IBM and Sytek as an Application Programming Interface (API) for client software to access LAN resources.By default it runs on port 139.NetBIOS gives the various information of the computers on a network, which includes computer name, username, domain, group, and many others.....!

The NBTSTAT Command :-NBTSTAT is the command for manually interact with NetBIOS Over TCP/IP. All the attributes (switches) used with nbtstat command and their usage can be viewed.At the command prompt type-

This information would give the intruder a list of shares which he would then use in conjunction with the Net Use command, a command used to enable a computer to map a share to it’s local drive, below is an example of how an intruder would map the C Share to a local G: drive, which he could then browse...!